Heat treating polyvinyl alcohol fibers in a molten metal bath



l .e. a s ge mp2 geing a ,35 o'ivwg ojdygvu Patented Mar. 5, 1%63 1 2 3,979,549 cluding ester and ether derivatives such as polyethylene HAT TREATING PSLYVKNYL ALCOHOL FBERS IN A MQLTEN BETA BATH Kigen liawai and Kenichi Taua'oe, Kurashilai City, Japan, assignors oi threefourths to Karasliiki Rayon 130., Ltd, Kurashilu-shi, Japan, a corporation of .l'apan, and one-- .5 fourth to Reduction Company, incorporated, New

Zorir, N.Y., a corporation of New York No Drawing. Filed May 29, 1958, Ser. No. 733,616 4 Claims. (G. 18-48) The present invention relates to the treatment of textile fibers. More specifically, this invention relates to an improved method for treating textile fibers including the step or" treating the fibers in a bath of molten metal.

Molten metal baths find considerable use in the treatment of textile fibers. For example, such baths are useful in the heat treatment of synthetic fibers such as polyvinyl alcohol, nylon, and polyvinyl chloride fibers. Also, molten metal baths have utility in the hot rolling or thermal contraction of thermoplastic textile fibers. Additionally, synthetic and natural fibers such as linen, cotton, wool, viscose rayon, and the like are dyed by techniques involving the use of molten metal baths.

Processes for the treatment of textiles involving passing the textile fibers through a bath of molten metal, especially processes involving eat treatment or hot rolling, have the serious disadvantage that mechanical or chemical damage to the fiber often occurs as a result of contact of the fibers with the molten metal or oxidation products of the metal. The molten metal tends to adhere to the surface of the fibe Also, the fiber is often stained by contact with the molten metal or with its oxidation products. The adhering metal and stains are extremely difiicult to remove from the textile fibers by chemical treatment with acids or other agents or by mechanical cleaning methods without impairing the quality of the textile.

It is an oblect of the present invention to provide an improved method for treating textile fibers including the step of treating the fibers in a bath of molten metal.

Other objects will be apparent from the following description of the invention.

In accordance with the present invention, textile fibers which are to be treated in a bath of molten metal are first coated with a protective coating agent which is efiective to prevent adhesion CU. the molten metal or oxides thereof to the fibers and which is efiective in preventing staining and other damage to the fibers. Subsequently, the fibers containing the protective coating are treated in the bath of molten metal without substantial damage to the fibers.

Protective coating agents which are employed in this invention are compounds which are readily applied to be treated in the metal bath and which are substantially non-reactive with the fibers to be coated. Additionally, the protective coating agents should be substantially nonvolatile at the tempe ature at which the molten metal is maintained. We have found that polyhydric compounds such as ethylene glycol, propylene glycol, and gylycerine are useful protective coating agents for practice of the invention. Derivatives of the polyhydric compounds, for example, mono or polyether derivatives such as ethylene glycol monoethyl ether, or monoor polyester derivatives such as ethylene glycol monostearate or ethylene glycol dilaurate can be used. Ether esters of the polyhydric compounds can also be used.

In addition to the above, polyglycols have been found to be especially suitable for use in the invention. Derivatives of the polyglycols can be employed. Polyethylene glycols ranging from about 200 to 7590 in molecular weight are commercially available and are especially useful in the invention. Polyethylene glycol derivatives in glycol 400 monostearate are also useful in the invention. Polypropylene glycols ranging from 150 to 2100 in molecular weight are commercially available and are very useful as protective coating agents in the invention. Derivatives of the polypropylene glycols including ether and ester derivatives can be used. Mixed polyethylene-polypropylene glycols having molecular weights up to 15,006 are available and are useful in the practice of the invention. Polyglycols and derivatives having molecular weights outside the above cited ranges can be used in the invention.

Compounds other than those described above can be used as protective coating agents according to this invention. Saturated aliphatic hydrocarbons such as tetradecane, hexadecane, parafiin wax, light lubricating oil, polyethylenes, polypropylenes, polyisobutylenes, and the like can be used. Aromatic hydrocarbons such as biphenyl can be used.

The protective coating agents are advantageously applied to the textile fibers by applicator rolls prior to treatment of the fibers in the molten metal bath. Alternatively, the fibers may be passed through an aqueous or organic solvent solution of the coating material. Other methods for applying the coating agent such as spraying will be apparent to those skilled in the art and can be used in carrying out this invention.

The amount of protective coating agent employed in the invention can vary. Amounts of coating agent in the range of about 0.2 to 30% based on the dry weight of the fiber are generally suitable with amounts of about 0.5 to 10% being preferred.

After the fiber has been coated with the protective coating agent, the fiber is passed to a molten metal bath wherein it is treated. Any of the commonly known low melting alloys including Woods metal, Roses metal, and various solders, which are liquid at the temperature desired for treating the fibers can be employed as the molten metal bath. Illustrative alloy compositions which can be used together with the melting point of each composition are given in the following table.

TABLE 1 Percentage by weight Melting point,

0 Bi 0 d Pb Sn 50.0 25.0 I 12. 5 68 50.1 26. 6 13. 3 68 50. 0 25. (J 25.0 93 40. 0 20. 0 40. 0 100 '7. 2 l7. 8 25. 0 100 The temperature and duration of the fiber treatment in the metal bath will vary depending upon the fiber and the desired treatment. Generally, lower temperatures such as 95 C. are employed for dyeing treatment while higher temperatures, for example, 230 C. are employed in heat treating fibers such as polyvinyl alcohol fibers. A general range of molten metal bath temperatures is about to 250 C. although temperatures outside this range are I sometimes used.

aoraaao which therefore canrea'dily be removed from the fiber by washing with water are conveniently and preferably employed in carrying out the present invention. If desired, the coating agents may be recovered and reused by procedures; which will be apparent to those skilled in the art."

The following examples illustrate the invention.

Example I Polyvinyl alcohol fiber, 200 denier/ 30 filaments, was coated with polyethylene glycol having a molecular weight of 200 through the use of applicator rolls. The fiber was coated with'the polyethyleneglycol in amount of about 1%. by weight of the fiber.

The coated polyvinyl alcohol was then passed through a 1 meter =long bath of molten Woods metal which was maintained at a temperature of 210 C. The fiber travelled at a speed of about 15 meters per minute entering the bath. In the bath the fiber. was stretched such that the speed of thefiber leaving theibath was about 75 meters per minute.

After treatment in the. molten bath, the polyethylene glycol'was readily removed from the fiber by washing with water.. The. fiber .thus obtained was free from adheringmetal ormetal oxides and evidenced no stains or. other damage. The. polyethylene. glycol ,had no discernible adverse efiect on'the fihen,

Example" 11 Polyvinyl alcohol fiber, 200 denier/ 30 filaments, was coated with a 10% solution of polyethylene glycol having a molecular weight of about 1000 in benzene through the use of applicator rolls. The fiber was dried and contained a coating of the polyethylene glycol in amount of about,1%.by weight of the fiber.

The coated polyvinyl alcohol'was then passed through a 2,meter long molten .bath of Woods metal'which was maintained at a temperature of about 220 C; The fiber travelled at -a speed'of about 100 meters per minute entering the bath. In the molten metal bath the fiber underwent'shrinkage such that the speed of the fiber leaving the bath was about 85 meters per minute.

After treatment in the molten bath, the polyethylene glycol was readily removed by washing with water. The fiber thus obtained was free from adhering metal or metal oxides and was not stained or otherwise damaged. The polyethylene glycol had no discernible adverse effect on the fiber.

Example III Acetate rayon, 100 denier/20 filaments was immersed in an aqueous solution containing about 5% of polyethylene glycol monolauryl ether. Therayon was dried and passed through a 1 meter long bath of molten Woods metal maintained at a temperature of about 130 C.

wherein the rayon was heat drawn. Residence time in the molten bath was about 1.5 to 6 seconds.

Upon completion ofthe heat treatment, the polyethylene glycol was removed from the fiber. No metal or metal oxide adhered to the surface of the rayon.

withrpolypropyleneglycol having a molecular weight of about 1000.- i

The coated polyvinyl chloridewas then heat treated for about 1.5; to 6 seconds in'a molten bath of, Woods metal which was maintained at a temperature of about 120- C.

4. After completion of the heat treatment, the. polypropylene glycol was removed from the monofilament. N0

staining or other damage to the monofilament'was ob served as a result of the treatment in the molten metal bath.

Ex'ample V Nylon, denier monofilament, was coated with ethylene glycol by immersion in a bath of ethyleneglycol.

The coated nylon monofilament was heat treated in a molten bath or" Woods metal which was maintained at a temperature of about C. for about 3 to 8-seconds,

After completion of the heat treatment, the ethylene glycol was removed from the nylon monofilament. by Washing with water. No adhesion of metal or metal oxides or staining or other damage had resulted from the treatment in the molten metal bath.

Woods metal which was employed in the above erev amples has of composition by weight of. 50% Bi, 12.5%'

Cd, 25% .Pb, and .l2.5%'Sn.

We claim:

l. The method of treating polyvinyl alcohol fibers which comprises-coating the fibers with a protective coatingagent which .is. efiective to prevent adhesion ofmetal and metal oxide products to the fibers and to prevent staining and other damage to the fibers as a result ofheat treatment otsaid fibers in molten metal maintained at a temperature efiective for said heat treatment, said coating agent being non-volatile at the temperature at which the molten metal is maintained and being removable from said polyvinyl alcohol fibers after passage through said bath, and said coating agent-consisting essentially of a member selected from the group consisting of polyethylene glycol, polypropylene glycol, and mono alkyl ethers and fatty acid esters thereof, heat treating the coated fibers in a heated bath of molten metal, removing said coating agent from said fibers after said heat-treating and subsequently recovering the treated fibers substantially undamaged and free of stains and adhering metal and metal oxidation products.

. 2. The method accordingto claim 1 Whe'reinsaid molten metalbath ismaintained at a temperature of about 210 C. to about 250 C..

3. The method according to claim 1 wherein said pro tective coating agent comprises a polyethylene glycol.

4. The method according to claim 1 wherein said protective coating agent comprises a polypropylene glycol.

References Cited in the file of this patent UNITED STATES PATENTS 1,856,475 Frost May 3, 1932 2,125,827 Ttirlcington -2 Aug. 2,.1938 2,139,640 Mall et al Dec. 6, 1938 2,282,568 Finzel May 12, 1942 2,395,396 Conaway Feb. 26, 1946 2,400,304 Hamel May 14, 1946 2,420,720 Pechukas et a1. May 20, 1947 2,474,502 Suchy June 28,1949 2,511,472 Kmecik lune'l3, 1950 2,518,193 Signaige Aug. 8, 1950 2,636,803 Cline et a1. Apr. 28, 1953 2,693,995 Hannay Nov. 9,1954 2,738,291 Stertz Apr. 9, 1957 2,886,475 Mc-Kay May. 12,1959

FGREIGN PATENTS 900,758- France July 9, 1945 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NOQ s o79 e4o March 5, 1962 Kigen K-awai et a1,

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1 line 52 after "to insert the fibers to Signed and sealed this 8th day of October 1963.

(SEAL) Attest: EDWIN La REYNOLDS ERNEST W. SWIDER I Attesting Officer Ac ting Commissioner of Patents 

1. THE METHOD OF TREATING POLYVINYL ALCOHOL FIBERS WHICH COMPRISES COATING THE FIBERS WITH A PROTECTIVE COATING AGENT WHICH IS EFFECTIVE TO PREVENT ADHESION OF METAL AND METAL OXIDE PRODUCTS TO THE FIBERS AND TO PREVENT STAINING AND OTHER DAMAGE TO THE FIBERS AS A RESULT OF HEAT TREATMENT OF SAID FIBERS IN MOLTEN METAL MAINTANED AT A TEMPERATURE EFFECTIVE FOR SAID HEAT TREATMENT, SAID COATING AGENT BEING NON-VOLATILE AT THE TEMPERATURE AT WHICH THE MOLTEN METAL IS MAINTANED AND BEING REMOVABLE FROM SAID POLYBINYL ALCOHOL FIBERS AFTER PASSAGE THROUGH SAID BATH, AND SAID COATING AGENT CONSISTING ESSENTIALLY OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF POLYETHYLENE GLYCOL, POLYPROPYLENE GLYCOL, AND MONO ALKYL ETHERS AND FATTY ACID ESTERS THEREOF, HEAT TREATING THE COATED FIBERS IN A HEATED BATH OF MOLTEN METAL, REMOVING SAID COATING AGENT FROM SAID FIBERS AFTER SAID HEAT TREATING AND SUBSEQUENTLY RECOVERING THE TREATED FIBERS SUBSTANTIALLY UNDAMAGED AND FREE OF STAINS AND ADHERING METAL AND METAL OXIDATION PRODUCTS. 